1. Field
Aspects of the present invention generally relate to a printing method and apparatus which performs heating to fix ink.
2. Description of the Related Art
There is attention being focused on a field where large format resin sheets are used to make highly weatherproof prints used for outdoor display and the like. Japanese Patent Laid-Open No. 2001-212950 discloses a printer which performs ink-jet printing on a sheet having a resin layer, and performs heating to fix ink.
A vinyl chloride sheet, which is representative of large format resin sheets, is formed of a thermoplastic resin film. Generally, an adhesive agent with weak adhesion strength is coated on the rear face side from the printed face to which ink has been applied, and peeling paper is applied thereupon, to facilitate display thereof. The present inventor has found the following problems to occur when using such a resin sheet having peeling paper.
The thermoplastic resin film of the vinyl chloride sheet softens under application of heat. On the other hand, when heated, the moisture in the peeling paper on the rear face side evaporates, and the peeling paper shrinks. That is to say, shrinkage of the peeling paper causes the entire sheet to shrink.
Analyzing in further detail reveals that at the time of heating to fix the ink applied to the sheet, the evaporation of the moisture included in the ink robs heat therefrom in the form of vaporization heat, which affects shrinkage of the sheet. The sheet shrinkage changes depending on the amount of ink applied to the sheet for printing, and the regions to which the ink has been applied. That is to say, the amount of heat robbed due to vaporization heat differs for each printed article printed with a different image, so sheet shrinkage is not uniform.
Different shrinkage among printed articles is problematic when creating a display of multiple printed articles arrayed with no space therebetween. An image may not smoothly connect to the adjacent image, and portions where the images connect may be visually recognized to viewers as seam streaks. The human eye is sensitive to even slight streaks.